The effect of haemostatic agents on early healing of the extraction socket.

AIM: This study aims to explore the effect of two commercially available haemostatic agents (i.e., collagen sponge and oxide cellulose) on early healing of the extraction socket. MATERIAL AND METHODS: In a murine model, bilateral maxillary first molars were extracted and the sockets were filled with or without haemostatic agents. Histology, histomorphometry and immunostaining assays were performed on samples harvested on postextraction day 1, 3, 7 and 14. In vitro studies were also designed to investigate the effect of agents on the dynamics of pH and viability of cells. RESULTS: Early socket healing was delayed by both agents but with different patterns. The migration of cells was impeded by oxide cellulose on postextraction day 1 compared with the collagen and the control group. The proliferation and osteogenic differentiation of cells were delayed by both materials. Moreover, apoptosis of periodontal ligament cells was present in the haemostatic agent groups. These effects are attributed to the compression to periodontal ligament by both agents, the acidic niche caused by oxide cellulose, and the intense foreign body reaction and inflammatory response caused by the agents. CONCLUSIONS: The placement of haemostatic agents delay the early extraction socket healing via different biological mechanism.

Rhodococcus biphenylivorans sp. nov., a polychlorinated biphenyl-degrading bacterium.

A Gram-positive, aerobic, non-motile and rod-coccus shaped novel actinobacterial strain, designated as TG9(T), was isolated from a polychlorinated biphenyl (PCB)-contaminated sediment in Taizhou city, Zhejiang province, eastern China. The isolate was observed to grow at 10-45 °C (optimum 28-32 °C), pH 5.0-11.0 (optimum pH 7.0-8.0) and with 0-9.0 % (w/v) NaCl (optimum 0-3.0 %). Comparison of the 16S rRNA gene sequences of strain TG9(T) and other members of the genus Rhodococcus showed that strain TG9(T) shared highest similarities with Rhodococcus pyridinivorans DSM 44555(T) (99.4 %), R. rhodochrous DSM 43241(T) (99.2 %), R. gordoniae DSM 44689(T) (99.2 %) and R. artemisiae DSM 45380(T) (98.2 %). However, low levels of DNA-DNA relatedness (15-48 %), which are below the 70 % limit for prokaryotic species identification, were obtained by DNA-DNA hybridization. Strain TG9(T) was found to contain meso-diaminopimelic acid as the diagnostic diamino acid and arabinose and galactose in the whole-cell hydrolysate. Mycolic acids were found to be present. The major fatty acids were identified as C16:0, C16:1 ω7c and/or iso-C15:0 2-OH, 10-methyl C18:0 and C18:1 ω9c. The only menaquinone detected was MK-8 (H2). The major polar lipids detected were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, glycolipid and traces of some unknown lipids. The genomic DNA G+C content of strain TG9(T) was determined to be 62.8 %. The combined phenotypic and genotypic data show that the strain represents a novel species of the genus Rhodococcus for which the name Rhodococcus biphenylivorans sp. nov. is proposed, with the type strain TG9(T) (=CGMCC 1.12975(T) = KCTC 29673(T) = MCCC 1K00286(T)).

Giant calcifying epithelial odontogenic tumor after I-125 seed implantation: A case report.

Calcifying Epithelial Odontogenic Tumor (CEOT), also known as Pindborg tumor, is a rare odontogenic benign tumor. It was first reported by Thoma and Goldman in 1946 and defined as an independent tumor by Pindborg in 1957. Herein, we reported a CEOT case involving most of the mandible after I-125 implantation in a 53-year-old man. We cooperated with governmental and hospital departments to resect the tumors, reconstruct the mandible with a fibular flap graft, and properly dispose of the radioactive particles.

Novel Magnetically Driven Superhydrophobic Sponges Coated with Asphaltene/Kaolin Nanoparticles for Effective Oil Spill Cleanup.

Fast and effective cleanup of oil spills remains a global challenge. A modified commercial sponge with superhydrophobicity, strong absorption capacity, outstanding magnetic response, and fire resistance were fabricated by a facile and inexpensive route of dip-coated melamine sponge carbonization. The low-cost petroleum asphaltene and kaolin nanoparticles were used as the dip-coating reagent. High absorption capacity of the fabricated sponges allowed rapid and continuous removal of oil contaminants. Taking advantage of the good refractory property, the sponges can be used in burning conditions and directly reused after burning out of the absorbed oil. Reusability tests showed that the modified sponges still maintained high absorption capacity (>85%) after six regeneration and reuse cycles. These characteristics make the fabricated sponge a promising aid to promote effective in situ burning cleanup of oil spills, contributing as a magnetic oil collector and a fire-resistant flexible boom. An example usage scenario of the sponges applied to in situ burning cleanup of oil spills is described.

Extracellular organic matter from Micrococcus luteus containing resuscitation-promoting factor in sequencing batch reactor for effective nutrient and phenol removal.

Culture supernatant containing resuscitation-promoting factor (SRpf) from Micrococcus luteus was added to the sequencing batch reactor (SBR) for effective treatment of phenol-containing wastewater. SRpf acclimation significantly improved combined removal of phenol and nutrients. Moreover, the Illumina high-throughput sequencing analysis revealed that the SRpf boosted bacteria diversity, which enhanced the stability of the system under phenol stress. Addition of SRpf increased the abundances of Actinobacteria and Proteobacteria phyla which are involved in nutrient and phenol removal. Specifically, SRpf promoted Nitrosomonas and Nitrospira which participate in nitrification, family Comamonadaceae, genera Dechloromonas and Pseudomonas involved in denitrification, and Acinetobacter, Pseudomonas and Rhodocyclus which remove phosphorus elements. Moreover, the abundances of Bacillus and Klebsiella responsible for phenol removal as well as Pseudomonas and Acinetobacter were significantly increased after SRpf acclimation. These results show that SBR combined with SRpf acclimation provide optimal nutrient and phenol removal.

Effects of condensation and compressive strain on implant primary stability: A longitudinal, in vivo, multiscale study in mice.

AIMS: Surgeons and most engineers believe that bone compaction improves implant primary stability without causing undue damage to the bone itself. In this study, we developed a murine distal femoral implant model and tested this dogma. METHODS: Each mouse received two femoral implants, one placed into a site prepared by drilling and the other into the contralateral site prepared by drilling followed by stepwise condensation. RESULTS: Condensation significantly increased peri-implant bone density but it also produced higher strains at the interface between the bone and implant, which led to significantly more bone microdamage. Despite increased peri-implant bone density, condensation did not improve implant primary stability as measured by an in vivo lateral stability test. Ultimately, the condensed bone underwent resorption, which delayed the onset of new bone formation around the implant. CONCLUSION: Collectively, these multiscale analyses demonstrate that condensation does not positively contribute to implant stability or to new peri-implant bone formation.Cite this article: Bone Joint Res. 2020;9(2):60-70.

Acceleration of perchloroethylene dechlorination by extracellular secretions from Microbacterium in a mixed culture containing Desulfitobacterium.

The study was conducted to demonstrate the influence of extracellular secretions from Microbacterium on the reductive dechlorination of tetrachloroethene (PCE). A series of mixed cultures were established from a paddy soil sample. In the mixed cultures amended with extracellular secretions from Microbacterium, PCE was rapidly and completely converted into cis-1,2-dichloroethene (cis-DCE) and trans-1,2-dichloroethene (trans-DCE) within 40 days. The unamended mixed cultures showed weak signs of dechlorination after a pronounced lag phase, and trichloroethene (TCE) was accumulated as a major end product. This result means that amendment with extracellular secretions from Microbacterium shortened the lag phase, increased the dechlorination velocity and promoted the production of less-chlorinated chloroethene. The results were corroborated by defined subculture experiments, which proved that microorganisms from unamended mixed cultures could also be stimulated by extracellular secretions from Microbacterium. Desulfitobacterium was identified as the main dechlorinating population in all mixed cultures by direct PCR. Additionally, the 16S rRNA gene copies of Desulfitobacterium increased by one or two orders of magnitude with PCE dechlorination, which provided corroborative evidence for the identification result. The volatile fatty acids were monitored, and most interestingly, a close association between propionate oxidation and dechlorination was found, which has rarely been mentioned before. It was assumed that the oxidation of propionate provided hydrogen for dechlorination, while dechlorination facilitated the shift of the reaction toward propionate oxidation by reducing the partial pressure of hydrogen.

A novel approach to enhance biological nutrient removal using a culture supernatant from Micrococcus luteus containing resuscitation-promoting factor (Rpf) in SBR process.

A culture supernatant from Micrococcus luteus containing resuscitation-promoting factor (SRpf) was used to enhance the biological nutrient removal of potentially functional bacteria. The obtained results suggest that SRpf accelerated the start-up process and significantly enhanced the biological nutrient removal in sequencing batch reactor (SBR). PO4 (3-)-P removal efficiency increased by over 12 % and total nitrogen removal efficiency increased by over 8 % in treatment reactor acclimated by SRpf compared with those without SRpf addition. The Illumina high-throughput sequencing analysis showed that SRpf played an essential role in shifts in the composition and diversity of bacterial community. The phyla of Proteobacteria and Actinobacteria, which were closely related to biological nutrient removal, were greatly abundant after SRpf addition. This study demonstrates that SRpf acclimation or addition might hold great potential as an efficient and cost-effective alternative for wastewater treatment plants (WWTPs) to meet more stringent operation conditions and legislations.

Health risk assessment of migrant workers' exposure to polychlorinated biphenyls in air and dust in an e-waste recycling area in China: Indication for a new wealth gap in environmental rights.

Migrant workers who work and live in polluted environment are a special vulnerable group in the accelerating pace of urbanization and industrialization in China. In the electronic waste (e-waste) recycling area, for example, migrant workers' exposure to pollutants, such as PCBs (polychlorinated biphenyls), is the result of an informal e-waste recycling process. A village in an electronic waste recycling area where migrant workers gather was surveyed. The migrant workers' daily routines were simulated according to the three-space transition: work place-on the road-home. Indoor air and dust in the migrant workers' houses and workplaces and the ambient air on the roads were sampled. The PCB levels of the air and dust in the places corresponding to the migrant workers are higher than those for local residents. The migrant workers have health risks from PCBs that are 3.8 times greater than those of local residents. This is not only caused by the exposure at work but also by their activity patterns and the environmental conditions of their dwellings. These results revealed the reason for the health risk difference between the migrant workers and local residents, and it also indicated that lifestyle and economic status are important factors that are often ignored compared to occupational exposure.

The physicochemical/biological properties of porous tantalum and the potential surface modification techniques to improve its clinical application in dental implantology.

More rapid restoration and more rigid functionality have been pursued for decades in the field of dental implantology. Under such motivation, porous tantalum has been recently introduced to design a novel type of dental implant. Porous tantalum bears interconnected porous structure with pore size ranging from 300 to 600µm and a porosity of 75-85%. Its elastic modulus (1.3-10GPa) more closely approximates that of natural cortical (12-18GPa) and cancellous bone (0.1-0.5GPa) in comparison with the most commonly used dental materials, such as titanium and titanium alloy (106-115GPa). Porous tantalum is highly corrosion-resistant and biocompatible. It can significantly enhance the proliferation and differentiation of primary osteoblasts derived from elderly people than titanium. Porous tantalum can allow bone ingrowth and establish not only osseointegration but also osseoincorporation, which will significantly enhance the secondary stability of implants in bone tissue. In this review, we summarize the physicochemical, mechanical and biological properties of porous tantalum. We further discuss the performance of current tantalum dental implants and present the methodologies of surface modifications in order to improve their biological performance.

Culture-dependent and culture-independent characterization of potentially functional biphenyl-degrading bacterial community in response to extracellular organic matter from Micrococcus luteus.

Biphenyl (BP)-degrading bacteria were identified to degrade various polychlorinated BP (PCB) congers in long-term PCB-contaminated sites. Exploring BP-degrading capability of potentially useful bacteria was performed for enhancing PCB bioremediation. In the present study, the bacterial composition of the PCB-contaminated sediment sample was first investigated. Then extracellular organic matter (EOM) from Micrococcus luteus was used to enhance BP biodegradation. The effect of the EOM on the composition of bacterial community was investigated by combining with culture-dependent and culture-independent methods. The obtained results indicate that Proteobacteria and Actinobacteria were predominant community in the PCB-contaminated sediment. EOM from M. luteus could stimulate the activity of some potentially difficult-to-culture BP degraders, which contribute to significant enhancement of BP biodegradation. The potentially difficult-to-culture bacteria in response to EOM addition were mainly Rhodococcus and Pseudomonas belonging to Gammaproteobacteria and Actinobacteria respectively. This study provides new insights into exploration of functional difficult-to-culture bacteria with EOM addition and points out broader BP/PCB degrading, which could be employed for enhancing PCB-bioremediation processes.

Optimization of protein production by Micrococcus luteus for exploring pollutant-degrading uncultured bacteria.

The screening of pollutant-degrading bacteria are limited due to most of bacteria in the natural environment cannot be cultivated. For the purpose of resuscitating and stimulating "viable but non-culturable" (VBNC) or uncultured bacteria, Micrococcus luteus proteins are more convenient and cost-effective than purified resuscitation-promoting factor (Rpf) protein. In this study, medium composition and culture conditions were optimized by using statistical experimental design and analysis to enhance protein production by M. luteus. The most important variables influencing protein production were determined using the Plackett-Burman design (PBD) and then central composite design (CCD) was adopted to optimize medium composition and culture conditions to achieve maximum protein yield. Results showed that the maximum protein yield of 25.13 mg/L (vs. 25.66 mg/L predicted) was obtained when the mineral solution, Lithium L-lactate, initial pH and incubation time were set at 1.5 ml/L, 8.75 g/L, 7.5 and 48 h, respectively. The predicated values calculated with the model were very close to the experimental values. Protein production was obviously increased with optimization fitting well with the observed fluorescence intensity. These results verified the feasibility and accuracy of this optimization strategy. This study provides promising information for exploring highly desirable pollutant-degrading microorganisms.